Underground Restoration.

“For a year from September 2005, under the nose of the Panthéon’s unsuspecting security officials, a group of intrepid ‘illegal restorers’ set up a secret workshop and lounge in a cavity under the building's famous dome. Under the supervision of group member Jean-Baptiste Viot, a professional clockmaker, they pieced apart and repaired the antique clock that had been left to rust in the building since the 1960s. Only when their clandestine revamp of the elaborate timepiece had been completed did they reveal themselves.”